Global Patent Index - EP 1001432 A1

EP 1001432 A1 2000-05-17 - Method of testing random-access memory

Title (en)

Method of testing random-access memory

Title (de)

Prüfungsverfahren eines dynamischen Speichers

Title (fr)

Procédé de test d'une mèmoire d'access aleatoire

Publication

EP 1001432 A1 (EN)

Application

EP 98309192 A

Priority

EP 98309192 A

Abstract (en)

A method of testing RAM without destroying the stored data consists of looping through the locations to be tested (21, 28, 29), and at each location, inverting the data stored in the location (22), loading the inverted data from the location to a register (23), inverting the data in the register (24), writing the twice-inverted data back to the location (25) and comparing the actual content of the location with the content of the register (26). The test fails (27) if any of the comparisons fails, whereupon the test can be terminated. The test succeeds (30) if the all of the locations have been tested without any of the comparisons having failed. Further tests may be carried out at a selected location only, to test for short circuits between data bus leads. The method contains fewer memory access operations that the conventional method, so it will be faster. The method will also detect bits that can be changed but not changed back again, as well as stuck bits. <IMAGE>

IPC 1-7 (main, further and additional classification)

G11C 29/00

IPC 8 full level (invention and additional information)

G11C 29/10 (2006.01); G11C 29/52 (2006.01)

CPC (invention and additional information)

G11C 29/52 (2013.01); G11C 29/10 (2013.01)

Citation (search report)

[XA] US 5699508 A 19971216 - KHASHAYAR ABBAS [US]

Designated contracting state (EPC)

DE FR GB NL

EPO simple patent family

EP 1001432 A1 20000517; US 6567940 B1 20030520

INPADOC legal status


2003-12-03 [18D] DEEMED TO BE WITHDRAWN

- Effective date: 20030531

2001-01-24 [AKX] PAYMENT OF DESIGNATION FEES

- Free text: DE FR GB NL

2001-01-03 [17P] REQUEST FOR EXAMINATION FILED

- Effective date: 20001106

2000-05-17 [AK] DESIGNATED CONTRACTING STATES:

- Kind Code of Ref Document: A1

- Designated State(s): DE FR GB NL

2000-05-17 [AX] REQUEST FOR EXTENSION OF THE EUROPEAN PATENT TO

- Free text: AL;LT;LV;MK;RO;SI